RECOMMENDATIONS FOR CALCULATING REAL ENERGY CONSUMPTION

Transcription

1 RECOMMENDATIONS FOR CALCULATING REAL ENERGY CONSUMPTION L ONE MORT E N S E N & KIM B. WITTCHEN I E A E B C A N N E X P R O P O S A L - B U I L D I N G E N E R G Y E P I D E M I O L O G Y L O N D O N, 1-2 O C T O B E R

2 43,098 km mio inhabitants SBi / AAU 2

3 Three locations for Aalborg University AAU Main campus Key numbers 2014: Students: Employees: Turnover:360 mio AAU Esbjerg Off-shore eng. AAU-CPH

4 Mission Danish Building Research Institute, SBi: creates research-based knowledge that improves buildings and the built environment Research departments: Town, Housing and Property Construction and Health Energy and Environment

5 Energy and Environment Low energy buildings Efficient energy performance of existing building Environmental assessment Ventilation Lighting (natural and artificial) Support to building energy legislation Simulation and calculation tools

6 Heat balance for Danish buildings, here single family houses PJ Heating system Free heat Solar gains DHW Ventilation Windows Roof Ext. wall Floor 5 0 Before After Before After 2006 S B i / A A U 6

7 Replacing roof coverings 12,000,000 m² 10,000,000 8,000,000 6,000,000 4,000,000 Other PVC Thatched roof Roof tiles Fibre cement, incl. asbestos Built-up (flat roof) Glass Fibre cement (asbestos free) Metal plates 100% Cement tiles Asphalt board (sloping roof) 90% Renovated share 80% 70% 60% 50% 40% 30% 2,000, % 10% 0% S B i / A A U 7

8 Development in energy usage in Danish buildings 210,000 TJ. 200, , , , , , , ,000 Business-as-usual (BAU) Full BR compliance BAU + more strict roof requirements BAU + more strict wall requirements BAU + more strict window requirements BAU + longer roof service life BAU + all roofs upgraded untill 2050 BAU + mech. vent. and HRC BAU + solar domestic hot water All requirements more strict All requirements more strict + vent. & HRC 120, S B i / A A U 8

9 Energy upgrade Political focus on energy savings and low energy consumption in buildings Great potential for energy upgrading in existing buildings Challenge: Uncertainty in calculations of the expected energy consumption Calculated potential energy savings are rarely meet Lack of credibility of the energy calculations S B i / A A U 9

10 New buildings Building regulations sets the minimum energy requirements When applying for a building permit it must be documented that a new building complies with the energy frame Compliance with the requirements must be documented using a EN ISO based calculation tool, Be10, developed by SBi The calculated energy demand for the building is based on default/standardized values for energy supply, heating, ventilation, cooling and domestic hot water, and hence a good tool for benchmarking buildings The calculation is not suitable to say anything about the expected/real energy consumption of the building S B i / A A U 10

11 Existing buildings Concerning: renovation of an entire building, energy upgrading or performing maintenance and replacement of large or small building components Building Regulations give minimum component requirements If economic feasible requirements must be fulfilled Full replacement of building components must always fulfil the minimum requirements regardless of profitability Documentation method is similar to that of new buildings in practice Be10 calculations is often performed also for existing buildings in relation to energy upgrading Be10 is also the calculation engine for issuing an energy performance certificate (EPC) S B i / A A U 11

12 Initiative The building sector needed common guidelines for calculation of real energy consumption in relation to upgrading of buildings The Danish Association of Consulting Engineers pushed for development of a guideline on how to perform the calculations A project was launched supported by the building sector including consultants, owners, building operators and knowledge institutions S B i / A A U 12

13 Energy consumption before and after upgrade 2 guides (Building upgrade) A t e c h n i c a l guide a i m e d a t c o n s u ltants t h a t p e r f o r m e n e r g y c a l c u lations A c o m m u n i c a t i o n p a p e r a i m e d a t b u i l ding o p e r a t o r s and owners t o h e l p m a t c h e xpectations i n relation t o u n c e r t a i n t y S B i / A A U 13

14 Technical guide is designed to calculate a realistic estimated consumption in a building - not as a single figure, but as a range of how much energy is expected to be consumed energy calculations is based on Be10 to ensure reuse of the work already begun in the context of energy or building applications propose a method that change the default values to realistic input data for the building realistic estimates for energy consumption S B i / A A U 14

15 Uncertainty- communication Why is it that difficult to predict real energy consumption after building upgrades? Energy consumption Impact of weather conditions Cold year Reference year Warm year Cold year Reference year Warm year Before energy upgrading After energy upgrading S B i / A A U 15

16 Uncertainty - communication Why is it that hard to predict the real energy consumption after building upgrades? Energy consumption User behaviour office equipment Before Before Before Electricity (El) Heating (Varme) After After After 16 Laptop, no monitor Laptop, one monitor Stationary computer, two monitors

17 Uncertainty - communication Why is it that hard to predict the real energy consumption after building upgrades? Electricity saving increase heating demand Energy consumption Electricity (El) Heating (Varme) Total 17 Older 2-tube fluorescent light fittings (power 16.9/8.3 W/m²) 1-tube HF lighting (power 4 W/m²)